The invention relates to a process for the preparation of trialkyl orthocarboxylates (orthoesters O) by the electrochemical oxidation of alpha, beta-diketones or alpha, beta-hydroxyketones, the keto group being present in the form of a ketal group derived from C1- to C4-alkylalcohols and the hydroxyl group optionally being present in the form of an ether group derived from C1- to C4-alkylalcohols (ketals K) ; in the presence of C1- to C4-alcohols (alcohols A), the molar ratio of the sum of the orthoesters (O) and the ketals (K) to the alcohols (A) in the electrolyte being 0.2:1 to 5:1.